Modelling the Tower of Hanoi was one of the easiest props i have made this year, nice easy and simple to make. I used a torus to create the rings which goes around the shape and duplicated that and just made them bigger.
For the base all i needed to do was use a cube and flatten it a little and used the bevel tool to soften the ages. For the pool i used a poly cylinder and used the scale tool wider the bottom and thin the top. Place them together and you have your toy.